This invention relates to a spirit level with top window mounting.
More particularly, the invention is directed to spirit levels of the I-beam frame type and wherein the bubble vial assembly is mounted to the web of the I-beam for viewing of the vial generally horizontally from the side. In some levels of this type it is also desirable to view the vial generally vertically, as from the top or bottom, such as through a window disposed in a flange in the I-beam.
When both vertical and horizontal viewing is desired, it is preferable to provide a transparent window element between the I-beam flange opening and the bubble vial assembly to minimize entry of dirt and dust into the latter. Heretofore, it has been found difficult to provide a tight overall assembly wherein the window element would not rattle, and yet permit adjustment of the bubble vial to the proper exacting relationship with the I-beam flanges so that the level would be accurate.
The present invention solves the aforementioned problem in a simple, yet unique manner.
It is contemplated that the complete vial assembly includes a dummy portion which hold no vial and a vial holding portion adapted to be disposed on the opposite side of the web from the dummy.
It is also contemplated that the window element includes elongated upper and lower windows, with the upper window extending into the opening in the I-beam flange and the lower window being received by a recess in the vial assembly. A pair of locating ledges are disposed between the upper and lower windows and extend outwardly from the peripheries thereof.
In accordance with one aspect of the invention, the ledges are separated by end slots which receive a cut-out web portion of the I-beam frame.
In accordance with another aspect of the invention, when the upper window is disposed in the I-beam flange opening, the dummy portion of the vial assembly is positioned on one side of the web and holds the window element tightly in position against the flange. However, when the vial holder is placed on the opposite side of the web, a slight space is provided between the vial holder and adjacent ledge, thus permitting rocking adjustment of the vial holder before it is tightened to the web.